1. Field of the Invention
The present invention relates to a rear suspension for a vehicle and, more particularly, to a rear suspension having a trailing arm which can cope with a transverse force by controlling a toe when the vehicle is cornering and which can absorb vibration and noise without twisting a bushing. Ride comfort and handling safety are thereby improved.
2. Description of the Background Art
A suspension for a vehicle connects an axle shaft and a car body to each other, and controls a position of a tire with respect to the car body for ideal positioning during vehicle operation. The axle shaft is thereby prevented from directly transmitting impact or vibration from a road surface to the car body. Optimal handling safety, a reduction in damage to baggage and improved ride comfort are obtained.
A rear suspension having a trailing arm is illustrated in FIG. 5, in which the trailing arm 52 is connected to both sides of supporting shaft 51 transversely mounted on the car body by a rubber bushing. A hub carrier 54 rotatably supporting a wheel 53 is integrally formed with a rear portion of the trailing arm. Further, a shock absorber and a spring 55 are formed on an upper portion of the hub carrier 54 and connected on their upper ends with the car body.
According to the above-described suspension, in the case that impact or vibration from the road surface is applied to the wheel 53, the trailing arm goes up and down based on its connecting portion with the supporting shaft 51. At the same time, the vibration and impact are absorbed by the rubber bushing inserted in connecting portion of the supporting shaft and trailing arm, the shock absorber and the spring.
As shown in FIG. 5, the supporting shaft 51 is coupled to the car body by means of a bracket 58 having a cylindrical rubber bushing 57 mounted on a shaft 56. The shaft 56 protrudes to the outer side of the connecting portion of the trailing arm 52. Accordingly, when the transverse force F is applied to the wheel 53 when the vehicle is cornering, the wheel 53 is changed into a toe-out state thereby adversely affecting cornering safety. In other words, since the supporting shaft 51 and the trailing arm 52 are integrally formed with each other, when the transverse force F is applied to wheel 53, the wheel 53 is pushed in the direction indicated by the arrow and, at the same time, the supporting shaft 51 overcomes the elastic force of the rubber bushing 57 and is deformed as shown in broken lines in FIG. 5. The wheel is thereby changed to a toe-out out state with respect to the cornering direction. As a result, since the trailing arm's length is relatively long, a large moment (transverse force F.times.trailing arm's length 1) is obtained, such that the variation to the toe-out state is greatly increased.
As described above, when the wheel attains a toe-out state during cornering, the characteristics of the rear wheel are naturally bad and cornering is adversely affected.